Catalytic hydrogenation of levulinic acid in aqueous phase

The hydrogenation of levulinic acid (LA) yielding γ -valerolactone (GVL) has been examined in aqueous solution using various water soluble phosphine ligands in combination with the metal precursors [Ru(acac)3] and [RuCl3]. Using catalyst loadings of only 0.2 mol%, GVL could be obtained in yields up to 99% conversion and 97% selectivity along with a maximum turnover frequency of View the MathML source200molGVLmolRu−1h−1 within 5 h, using 3,3′,3′′-phosphinidynetris(benzenesulfonic acid) trisodium salt (TPPTS) and Ru(acac)3 as catalytic system. In addition, a ruthenium–phosphine complex immobilized on the amphiphilic copolymer PS-PEG was examined under the same conditions and gave 90% conversion of LA in 24 h.